P T. XYZ is a manufacturing company that produces corrugated carton boxes. PT.XYZ uses a make to order (MTO) manufacturing system in its production process.AO's cardboard products (from customers of PT. AO) are the object of researchbecause the number of requests has the highest number of orders for the productin a one-month period. The problem with AO products is that productionperformance is not in accordance with customer demand. The purpose of thisresearch is to increase production performance by minimizing waste using a leanmanufacturing approach. By using the Process Activity Mapping and ValueStream Mapping tools, the identified wastes are waste of waiting, overprocessing,defects, and transportation. Other results obtained were manufacturing lead timebefore repair of 284.49 minutes and a process cycle efficiency percentage of60.44% with the highest production achievement is 22,260 cardboard sheets. Tofind the root causes of waste, the Fault Tree Analysis (FTA) method and fishbonediagram are used. The results of the analysis of the root causes of waste show thatthe dominant root causes are the location of the mold on the 2nd floor, the machinestops during the production process, the operator's lack of knowledge aboutinspection activities, the absence of machine maintenance, and the tools nothaving a fixed location. Recommendations for an improvement that can be givenare to design racks for the 1st floor, create standard operating procedures (SOP)for operators and machine maintenance SOPs, combine inspection activities, andadd utility cart. The results of this proposed improvement are a decrease in MLTto 272.82 minutes, and an increase in PCE percentage to 63.02%. With the MLTvalue after repair, the production of cardboard sheets that can be produced withthe new MLT is 23212 cardboard sheets.